1. Field of the Invention
The present invention relates to an electronic circuit field, in particular, relates to a circuit for controlling the operation of a backup power supply.
2. Background of the Related Art
For many types of electronic equipment, especially for those used in the telecommunication systems, the finance systems, and the internet servers etc., the interruption of power supply is not permitted. To guarantee a constant power supply without any interruption, the backup power supply must maintain sufficient energy for a long period of time. Normally, the secondary batteries are employed as a backup power supply, for example, the lead-acid batteries, the lithium-ion batteries and the energy batteries. The lithium-ion batteries and the energy batteries are configured in small size and high energy density, and are convenient for transportation.
However, the lithium-ion batteries and the energy batteries require multiple functional circuits for regular charging and discharging. When used as power supply source, the electric power is supplied to both the external electronic equipments and the internal functional circuits. Furthermore, such batteries continue to supply power to the internal functional circuits, even though they have stopped supplying power to the external electronic equipments. As a result, the backup power supply loses electric energy during the non-working mode, and may not work properly during emergency.